Recently, electronic devices are continuously developed with the development of integrated technology, bonding technology and mounting technology of semiconductor devices used in wiring of electronic devices, high-density electronic packages and high-density printed circuit board. Especially, a rapid development thereof occurs in electronic devices using broadband, e.g. mobile communication devices.
As a component of such electronic devices, printed circuit board develops in a direction of a higher degree of multilayer printed circuit boards and more precise wiring. In order to increase the signal transmission speed to a level desired for speeding up the information processing, an effective way is to reduce the dielectric constant of the used materials. In order to reduce the transmission loss, an effective way is to use the materials having a lower dielectric loss tangent (dielectric loss).
While the electronic technology rapidly develops, people are pursuing environmental protection. However, the conventional high-frequency high speed materials basically use halides, antimonides and the like to achieve the object of flame retardance. When the halide-containing copper foil laminate is on fire and combusts, it will emit a great amount of smoke and an undesirable odor, as well hydrogen halide gas having a great toxicity and a strong causticity, which not only pollute the environment, but also endanger human health. Currently, the epoxy resins corresponding to the phosphorous-containing phenanthrene type compound DOPO or ODOPB are generally and industrially used to achieve the common FR-4 and the flame retardance. The phosphorous-containing phenanthrene type compound DOPO or ODOPB, however, still has a greater water absorption and a great effect on the dielectric constant and dielectric loss tangent.